No longer available for purchase - Information for reference only
The GTOCP4 Control Box, is now available as an upgrade for all GTO mounts that we have produced since 1998. It is also included with all new mount orders.Information regarding the GTOCP3 in this document is provide for reference.
Mounts that can use the GTOCP3 control box: All GTO mounts - All Mach1GTO, 900GTO, 1100GTO, 1200GTO, 1600GTO, 3600GTO and prior models 400GTO and 600EGTO. The parameters of the GTO control box depend on the gear ratio and motor of the mount. Therefore, the control boxes are not necessarily interchangeable from one model to another. For instance, the control box for the 400 mount cannot be used with the 1200 mount. However, the control box for the Mach1GTO, 900GTO, 1100GTO, 1200GTO and 1600GTO mounts are interchangeable. Please check with Astro-Physics before substituting control boxes. Additional information is provided at the bottom of this page.
Please note the following additional considerations if you are upgrading from a GTOCP1 control box:
The GTOCP3 Control Box contains all of the circuitry to drive the two servo motors and the logic required to circumnavigate the sky. It functions as "the brains" of your mount translating the commands that are received from external software (Keypad, planetarium program or other software) into electrical signals to the motors to produce movement and other critical functions. It also makes all the required calculations and determines the safe and proper path for GoTO slews.
The main function of the GTO Control Box is
to drive the R.A. and Dec. motors, which are DC
servos with built-in shaft encoders. The rotation
rate and precise number of rotations of each motor is controlled
with a servo feedback loop. The servo looks at the return
pulses from the shaft encoders and adjusts the
current to the motor so that the rate is identical
to the commanded rate (i.e. from .25x sidereal
to 1200x sidereal). The precise number of motor rotations is translated
into incredibly accurate R.A. and/or Dec. distances.
This electronics box is mounted directly on the R.A. axis of the 1200 and 900 mounts (as shown in the photo), on the side plate of the 1600 and 3600 and is a stand-alone unit for the Mach1, 1100, 400 and 600E mounts. The freestanding unit attaches to your pier or tripod with the handle on the fabric pouch or the Control Box Adapter (CBAPT) both included with the Mach1GTO.
The GTOCP3 shipped with the Mach1GTO mount is completely black-anodized to match the mount. The control boxes shipped with the 900GTO, 1100GTO, 1200GTO, 1600GTO and 3600GTO mounts have a black-anodized panel where the connectors are located and the remainder of the box is painted the same cream-white as the mounts.
| Control Features
The command language protocol that is programmed into the microcontroller of the GTOCP3 Control box allows the sophisticated control functions of your mount. Please keep in mind that the software that communicates with the mount will determine which commands are utilized. For instance, although the control box is programmed to include a command that can implement a timed guide move, if the software does not issue the command, this feature cannot be used.
For optimum utilization of the advanced functions in the command language protocol, we recommend that you control your mount with either the GTO Keypad, software that utilizes the ASCOM V2 driver or the Astro-Physics Command Center (APCC). All of these control options were written by Astro-Physics. For more information, see: Control Your GTO Mounts with Your Keypad, Computer or Mobile Smart Devices.
Here are some of the key features and functions available in the latest versions of the GTOCP3 Control Box:
| Mechanical Features
|Dimensions of servo box||4.9" x 4.9" x 1.8" (12.5 x 12.5 x 3.4cm)|
|Weight||1.5 lbs. (0.7 kg)|
|Suggested power sources||Portable 12V battery pack, auto or marine battery
110 to 12V DC Power Supply (5 amp minimum, regulated and well-filtered to prevent spikes), like our 13.8-volt, 5-amp power supply (PS138V5AC) . For the 1200GTO mount with a heavy load in colder climates and for the 3600GTO, we recommend the 15-volt, 12-amp power supply (PS15V12AC)
|Standards||Meets FCC and CE standards|
Astro-Physics GTO Servo Motor Drive System - Model GTOCP3 - Manual
Chip Upgrade for GTOCP3 Control Box
If you already own the GTOCP3 control box, you may wish to consider upgrading the ROM chip to take advantage of the newest features and bug fixes which can impact your mount's performance.
Here is list of the Revisions to the ROM chip. (PDF document)
Check our website for upgrade procedures and information to obtain the most recent ROM chip.
Purchasing a Used GTOCP2 or GTOCP3 Control Box via the Second-Hand Market|
There will be a number of used CP2 and CP3 control boxes becoming available through second-hand markets, such as Astromart, once the CP4 is released. The buyer will need to be aware of a couple things to ensure that it will work with his or her mount.
There are no concerns if the seller's control box is from a Mach1, 900, 1100, 1200, or 1600 mount and being used on the buyer's 900 or 1200 mount as the mounts' "personalities" are the same.
However, if the control box is either coming from a 400, 600 or 3600 mount or going to those mounts, then it will be necessary to change the "personality" setting of the control box. Please call Astro-Physics to learn more.
It is recommended that a CP2 or CP3 box have the latest chip installed in order to maximize its performance and safety. Please call Astro-Physics to learn which chip is appropriate for your box, or check the technical support section of our website.
Although a CP3 will perform well with a "Q" and above chip, a "V" or later chip is recommended to maximize performance, as well as being required to use the APCC software.
Note that a CP2 box cannot utilize the APCC software.
Finally, it is very important that PEM is turned off in the Keypad and disabled in the AP V2 ASCOM driver and APCC until a new curve is run. If this is not done, then you will experience large and incorrect surges in the PE of the mount, as you will be entering false PE curves that are from the previous owner's mount into yours. Once you run a new curve, you can turn the PE back on.
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Inc. - All Rights Reserved
This page was last modified: March 10, 2019
11250 Forest Hills Road, Machesney Park, IL 61115, U.S.A.
Phone: 815-282-1513 Fax: 815-282-9847