SRS Labs CTC100, Руководство пользователя

Страница: 22 / 177

Introduction 10
CTC100 Programmable Temperature Controller
Output card overheated: Either the resistance of the heater is less than 10 ohms; the
positive and negative terminals are shorted to each other; the ambient temperature is too
high; or the CTC100
is not working. Try reducing the maximum output voltage
or current, and make sure the front panel fan is running.
±10V analog I/O channels
Each of the four analog I/O channels has a BNC connector on the back panel of the CTC100.
The outer shell of the connector is grounded.
Each analog I/O channel can be an input (±10V, 24-bit ADC) or an output (±10V, 16-bit
DAC).
t as accurate as the dedicated sensor inputs and heater outputs, the analog
I/O channels can be used to read temperature sensors and drive heaters. If used to drive a heater,
each analog I/O channel can only supply up to 30 mA of current. Furthermore, because of their
limited accuracy, when set to 0 V the analog outputs may still feed a small amount of power to the
heater. This residual current can be eliminated by placing a diode in series with the heater and
increasing t
Lo Lmt setting to about 0.5V (to prevent integral windup).
R elay s, digital I/O , and virtual channels
The CTC100 has four relays, each rated for up to 5A of current. The connector for the relays is a
single 12-pin pluggable terminal block. The four relays are l and each relay
closed normally
state when the CTC is turned off, when its
outputs are not enabled, or when the relay is set to 0. In this state, t
the relay is set to 1 and the outputs are
enabled, the relay is activated: the s
unconnected.
The relays appear on the CTC100 display as a single 4-bit integer value between 0 and 15. If no
relays are activated, the value is 0. Each relay, if activated, adds the following to the displayed
value:
Rela y
A
B
C
D
V a lue
1
2
4
8
Therefore, if the relay channel 6 , relays B and C are activated. Conversely, setting the relay
channel to 6 activates relays B and C, and deactivates the other relays. To set an individual relay
from a macro or serial port without affecting the states of other relays, use a bitwise operator; for
example, the remote command
relays |= 4
activates relay C, while the remote command
relays &= 11
remote commands.