Stanford Research Systems SR245 Computer Interface Module

Description

Stanford Research System SR245 Computer Interface Module. Item came from a working environment. Additional Information from SRS:
The SR245 Computer Interface module is a powerful tool for data acquisition. It provides both an analog and a digital interface between your computer and your experiment.
Eight analog I/O ports
8-bit digital I/O port
Two TTL I/O ports
RS-232 and GPIB interfaces
3500 point sample memory
Simple command structure
SR245 Specifications
Analog Ports
Configuration
Any number of the eight ports may be designated under program control as input ports, the rest default to output ports.
Inputs
1 MΩ impedance, ±10.24 VDC range, protected to 40 VDC. 13-bit resolution (2.5 mV). 0.5 % accuracy. Input offset <2.5 mV. Maximum A/D rate is 2 kHz.
Outputs
<1 Ω impedance. Short circuit current limit is 20 mA. 13-bit resolution (2.5 mV), 0.5 % accuracy. Output offset <2.5 mV
Digital Ports
Type
Two front-panel I/O TTL bits, one 8-bit digital input port, one 8-bit latched digital output port
Front-panel inputs
Input impedances >100 kΩ. Minimum pulse width is 200 ns. Maximum count rate is 4 MHz. Logic one >3 VDC, logic zero <0.7 VDC. Inputs protected to ±10 VDC
Front-panel outputs
Can drive 50 Ω loads to TTL levels
General
Interfaces
IEEE-488 (GPIB) and RS-232 (110 baud to 19.2 kbaud)
Power
+24 V/60 mA, 24 V/60 mA, +12 V/20 mA, approx. 8 watts
Mechanical
Single-width standard NIM module
Input/Output Commands
I n=0 to 8
Designates the first n analog ports as inputs, the remainder become outputs.
? n=1 to 8
Returns the value of the designated analog port.
?B n=1,2
Returns the value (0 or 1) of the designated digital port.
?D
Returns the value of the 8-bit digital input port.
?S
Returns the value of the status byte, and clears the status byte.
C
Configures B2 as an input and resets the B2 counter.
?C
Returns number of pulses occurring at B2 since the previous ?C.
S=
Sets the analog port n (which must be designated as an output) to the value x (x=-10.237 to +10.237 V). n=1 to 8
SB=
Designates digital bit n as output and sets its value to m (n=1, 2 and m=0, 1)
SB=I
Designates the selected bit as an input (n=1, 2)
SD=
Sets the 8-bit digital output port to the value n (n=0 to 255)
SM=
Sets the GPIB SRQ mask to the value n (n=0 to 255)
Trigger Commands
MS
Sets the synchronous mode. Responses to ? commands are returned after next trigger.
MA
Sets the asynchronous mode (default). Responses to ? commands are returned after command is received.
T
Designates every n
th
pulse at B1 as a trigger (n=1 to 32,767)
DT
Masks the trigger input so that no triggers are recognized
ET
Unmasks the trigger input
PB
Outputs a 10 µs TTL pulse at digital port n (n=1, 2)
P/
Outputs a 10 µs TTL pulse at B2 each n
th
trigger (n=1 to 255)
Scan Commands
SC,:
Scans the list i..k of analog ports or digital port for n triggers. Total # of samples may not exceed 3711. (i..k=1 to 8, D)
ES
Ends the current scan immediately and resets the point sending counter.
N
Sends the next point of stored scan
?N
Returns # of points scanned
A,
Adds n × 2.5 mV to the value of analog port 8 (must be positive) on every i
th
trigger (n,i=1 to 255)
SS,:
Scans the list i..k of analog ports or digital port for n triggers. Data is sent in a 2 byte binary format while scan is in progress.(i..k=1 to 8, D)
X
Sends the data of a stored scan in 2 byte binary format.
Miscellaneous Commands
MR
Master Reset. Returns the SR245 to its default values.
W
Introduces a delay of (n × 400 µs) before sending each character over the RS-232 interface. (n=0 to 255)
Z,
Changes the end-of-record characters sent by SR245 to those specified by the ASCII codes, i...k