RD Controls Hardware Release Note 28.2

Preliminary Design

C1080 Multibus Interface Module

CAMAC Function Codes

R.E.West

September 1, 1992

Introduction

The beamline control system interfaces with modules residing in multibus crates used to obtain information from and to control devices in the various beamline cryogenic systems. A cryogenics multibus crate may contain a maximum of two A/D-D/A modules, two actuator controller modules, two digital status and control modules, and one temperature resistor module.

An A/D-D/A module contains 32 A/D data channels and 2 D/A channels. For interfacing purposes, the A/D section and the D/A section are each identified as a separate device having multiple data channels. Because there may be two A/D-D/A modules in a multibus crate, the A/D device is considered to have a maximum of 64 (2 * 32) data channels and the D/A device is considered to have a maximum of 4 (2 * 2) data channels. The other multibus module which is treated as a collection of distinct devices is the digital status and control module. Using this scheme of devices and channels, Table 1 lists the maximum configuration a multibus currently may contain.

CAMAC Function Codes

Because a multibus device (e.g., digital status) may have as many as 80 channels, it is not possible to use only one CAMAC operation to read information from a specific device and channel. It is necessary to first perform a write operation (F17A0) to specify the initial channel number. After that, each read operation directed to a particular device returns the requested information and then increments the channel number. Note that only one channel number variable is maintained. Each time data is to be obtained from a different device, the initial channel number must be specified again. A minimum of 7 bits is required to specify the largest channel number currently being used. A field width of 8 bits is actually used, so the maximum channel number which may potentially be used is 255.

F0An

Read a 16-bit data word and then increment the channel number. A valid reading is returned only for the A/D device and the temperature device. A request for any other device or for a channel number greater than the maximum for the requested device results in a no Q. The average value is calculated using the previous eight data readings.

A0 - read A/D channel
A1 - read A/D channel averaged over the last 8 readings
A2 - read temperature channel
A3 - read temperature channel averaged over the last 8 readings

F0A12

Read the current value of the channel number, which is the number of the channel to be used for the next read or write operation directed to the channel of a device. Note that this channel value will not be the same as the value initially specified if read or write operations have been issued to the device and have caused the channel number to be incremented.

F0A13

Read the selected table ID number and the entry offset. Parameter tables may be associated with particular device and channel combinations. This operation selects the initial entry of a particular table to be referenced by a table read or write operation. As with the channel number variable, there is only one table/offset variable pair. Hence, the table ID and initial entry offset need to be specified prior to referencing parameter table data for a different device.

bits 15 - 8: table ID

bits 7 - 0: entry offset

F0A14

Read a 16-bit data word from the selected parameter table of the selected device and channel and then increment the entry offset to the next word. Note that the channel number is not incremented by this operation nor by the the F1A1.

F1A0

Read engine requested position.

F1A1

Re0d engine tolerance.

F1A2

Read actuator requested position.

F1A3

Read actuator tolerance.

F1An

Read status register and then increment the channel number

A6 - TTL latch (0 = OPEN, 1 = CLOSED)
A7 - latching relay (0 = OPEN, 1 = CLOSED)
A8 - TTL status (0 = OPEN, 1 = CLOSED)
A9 - engine (set of TTL status channels)
A10 - compressor status (set of TTL status channels)
A11 - actuator controller

bit 0: local/remote (0 = REMOTE, 1 = LOCAL)

F1A13

Read LAM mask

F1A14

Read LAM request register

F6A0

Read module number

F6A1

Read version number

F6A3

Read FOP status

F6A4

Read FOP data

F6A5

Read the hardware serial number of the module

F8A0

Test LAM

F9A0

Module reset

F10A0

Clear LAM

F17A0

Write the channel number

F17A1

Write the table ID number and the entry offset

bits 15 - 8: table ID

bits 7 - 0: entry offset

F17A2

Write a 16-bit data word to the current entry in the selected table and then increment the entry offset to the next word

F17A3

Write engine requested position.

F17A4

Write engine tolerance.

F17A5

Write actuator requested position.

F17A6

Write actuator tolerance.

F17A13

Write LAM mask

F17A14

Write LAM request register

F19A2

Write FOP command

F19A3

Write FOP data to buffer

F19An

Set to 0 (OFF or OPEN) or 1 (ON or CLOSED) and then increment the channel number

A4 - TTL latch (0 = OPEN, 1 = CLOSED)
A5 - latching relay (0 = OPEN, 1 = CLOSED)
A6 - momentary relay (0 or 1 = pulse the relay)
A7 - engine (set of momentary relays)
A8 - compressor status (set of momentary relays)

F24A0

Disable LAM

F26A0

Enable LAM