Lake Shore Model 332 Temperature Controller User’s Manual
3.8 ANALOG
OUTPUT
When Control Loop 2 is not being used, its output can be configured as an analog voltage output. When
properly configured the Model 332 has a single analog output on Pins 7 and 8 of the terminal block at
the rear of the instrument. It is normally used to send a voltage proportional to temperature to a strip
chart recorder or separate data acquisition system. The output can also be manually controlled as a
voltage source for any other application. Refer to Paragraph 4.16 and the ANALOG command in
Chapter 6.
The analog output is a variable DC voltage source that can vary from –10 V to +10 V. It is highly
recommended that the analog output be configured for 1 W maximum output. When configured for 1 W
the output source impedance drops to 0.01
Ω
. For complete analog output specifications refer to
Paragraph 1.3.
The analog output may also be configured to supply 10 W maximum output. In this configuration the
output specifications are the same as the loop 2 output specifications given in Paragraph 1.3.
The output for the analog outputs is available from positions 7 and 8 of the detachable RELAY and
ANALOG OUTPUT Terminal Block. See Figure 3-5. The terminal marked positive (+) is the output
voltage terminal, the terminal marked negative (–) is the ground and is attached to chassis ground
inside the instrument.
It is not recommended to attach the analog output ground to a ground outside the instrument. The
output should be read by an instrument with an isolated or differential input wherever possible.
Connecting to an external ground can cause noise in the analog output voltage or the sensor input
measurement. If this cannot be avoided, try to keep the chassis of the two instruments at the same
potential with a ground strap.
3.9 RELAYS
The Model 332 has one high and one low relay. They are most commonly associated with the alarm
feature. The relays can also be placed in manual mode and controlled directly by the user from the front
panel or over the computer interface. Refer to Paragraph 4.15 and the RELAY command in Chapter 6.
Normally Open (N.O.), Normally Closed (N.C.), and Common (COM) contacts are available for each
relay. All contacts (including common) are isolated from the measurement and chassis grounds of the
instrument. If a relay is inactive (Off), it will be in its normal state of open or closed. When the relay is
active (On), it will be in the opposite state.
Terminal Block Connector
Lake Shore P/N 106-739
1
2 3
4 5
6 7 8
Use screwdriver to
lock or unlock wires
Insert wire
into slot
Slides into slot at
rear of Model 331
Pin
Description
Pin
Description
1
2
3
4
Relay 1 – Normally Closed (NC)
Relay 1 – Common (COM)
Relay 1 – Normally Open (NO)
Relay 2 – Normally Closed (NC)
5
6
7
8
Relay 2 – Common (COM)
Relay 2 – Normally Open (NO)
Loop2/Analog Voltage Output – Hi (+)
Loop2/Analog Voltage Output – Lo (–)
Figure 3-5. RELAYS and ANALOG OUTPUT Terminal Block
3-10
Installation
