Intended outline

• The Bird's Eye View
• Setting up the PMAC-VME
  • Serial Communications
  • VME Communications
• Motor Hardware Connections
• PMAC variables
  • I-Variables
• PMAC Commands
• EPICS variables

Jumpers E44-E47 determine the baud rate. The communications are 8-N-1 by default, but if E49 is "off," it's odd parity. XON/XOFF is not supported.

While you are communicating with the PMAC through the serial cable, nothing should be trying to access it through the VME bus. To quote from the PMAC manual:

Either the serial port or the bus port is the active response port....
PMAC powers up/resets with the serial port as the active response port.
However, any command received over the bus port makes the bus port the
active response port....

A subsequent command from the serial port does not automatically make
the serial port the active response port again, so it is possible that PMAC
will respond to a command over the serial port by sending data to the bus 
port.... To make the serial port the active response port again, you must 
send a <CNTRL-Z> to PMAC.

To check communications, type requests for data, such as "I0" (India-zero). The response should be the value of the variable. The following variables set certain communication paramaters:

To set a variable, simply type {variable}={value}. For example, to set variable I9 to report back long responses in hexidecimal, type:

I9=3
and hit return.

When you can reliably talk to the PMAC through the serial port, it's time to set up VME communications.

• VME-bus Communications

R[H]{address}[,{no. of bytes}]

• R is the read command
• H will report back in hexidecimal
• {address} is either X,Y, or L folllwed by an optional colon and an integer specifying the value (0 - 65535 or $0000 - $FFFF)
• {no. of bytes} is a number from 1 to 16 which defaults to 1.

RHX:$0783,10

To write the data, we use the "W" command which is simply

W{address},{value}[,{value}...]

For example,

WX$0783,$09,$04,$80,$7F,$A2,$02,$A5,$70,$E0,$80
would take care of the second PMAC in our VME crate.

At this point, double check the settings and send the save command to load the parameters into non-volitale memory. Then reset the card with the $$$ command.

The save command must be used to store these variables in memory before the card is powered down or reset.

• I-Variables

The 160 general I-variables run from I0-I99 and from I940-I999. We have already seen a few above in setting up communications correctly.

The motor-specific I-variables are grouped by hundreds. I100-I199 are for motor #1, I200-299 are for motor #2, etc. The standard method of specifying a particular motor-specific variable without specifying the exact motor is to use an "x" in the hundreds spot: Ix00, for example. This variable enables or disables motor "x."

At the most basic level, the following I-variables must be correctly set:

# Addresses---where to find things

• Motion

• Coordinates

• From PMAC-VME P2 to Motor Amp

• From Motor Amp to Servo Motor Amplifier Buffer

• From Servo Motor Amplifier Buffer to Motor Break-Out Box

  ____                                          ____
 /    |                                        |    |
|19 18|                                        |10 9|
|     |                                        |8  7|
|     |  36-pin Centronix "D" connector        |6  5 ]  10-pin ribbon cable
|     |                                        |4  3|
|36  1|                                        |2  1|
 \____|                                        |____|

 1 - JM1                           36 - JM2
 2 - Drive +                       35 - Drive -
 3 - Drive +                       34 - Drive -
 4 - +5 V (pin 2/10-pin)           33 - +5 GND (pin 3/10-pin)
 5 - Encoder A (pin 5/10pin) JM4   32 - Encoder B (pin 7/10pin) JM5
 6 - (pin 9/10pin)           JM6   31 - (pin 4/10pin)
 7                                 30
 8 - GND                           29 - GND
 9 - + OverTravel Normally Open    28 - + OverTravel Normally Closed
10 - + Limit Normally Open         27 - + Limit Normally Closed
11 - Home Normally Open            26 - Home Normally Closed
12 - - Limit Normally Open         25 - - Limit Normally Closed
13 - - OverTravel Normally Open    24 - - OverTravel Normally Closed
14 - GND                           23 - GND
15 - Address 0 JM3                 22 - Address 1 JM3
16 - Address 2 JM3                 21 - Address 3 JM3
17 - Address 4 JM3                 20 - Address 5 JM3
18 - Address 6 JM3                 19 - Address 7 JM3

• Break-out Box to Motor

JM1 - Ties Centronix pin 1 to ground
JM2 - Ties Centronix pin 36 to ground
JM3 - Sets address of motor by tying Centronix pins 15-22 to ground
JM4 - Encoder Type:  Will read [5] (5k-type) or  [1] (6k-type)
JM5 - Encoder Type:  Will read [7] (5k-type) or  [8] (6k-type)
JM6 - Encoder Type:  Will read [9] (5k-type) or [10] (6k-type)

• Motor Pin-out

1 - Drive +
2 - +5 V
3 - Encoder A
4 - Encoder B
5 - GND
6 - Drive -

This page CONSTANTLY under construction...