3.10 Connecting a Logic Probe to the Logic Input
Module
To measure logic signals, connect a logic probe (the 702911, 702912, 700986, or 700987) to a logic
input module (the 720230).
CAUTION
• Applying a voltage greater than the limits listed below may damage the logic probe or the
instrument. For frequencies above 1 kHz, damage may occur even if the voltage is less
than the limits listed below.
Maximum input voltage (at a frequency of 1 kHz or less)
• Logic probes 702911 and 702912: 35 V
• High-speed logic probe 700986: 42 V (DC + ACpeak)
• 700987 isolated logic probe: 250 Vrms (however, ACpeak must be less than 350 V, and
DC must be less than 250 V)
• For logic probes 702911 and 702912 and high-speed logic probe 700986, the eight input
lines of a single pod share the same ground. Also, the instrument’s ground and the grounds
of each pod are connected. Do not apply signals with different common voltages to each
input line. Doing so may damage the instrument, connected logic probes, and connected
devices.
• The input terminals of an isolated logic probe are isolated from each other and from the
DL850/DL850V.
• Turn off the DL850/DL850V before you connect or remove a 26-pin connector from the
logic signal input connector.
• Do not stack the isolated logic probes during use. Also, allow enough space around the
probes to avoid a temperature increase inside the probes.
• Do not use the YOKOGAWA 700985 logic probe with the DL850/DL850V. The 700985
is shaped so that it can be connected to the logic signal input connector of the DL850/
DL850V, but it is not electrically compatible with the DL850/DL850V, so connecting the two
could damage the DL850/DL850V or the 700985.
About the Logic Probe
Types of Logic Probes
YOKOGAWA provides the following four types of probes (as accessories) for connecting to the logic
signal input connector of the DL850/DL850V.
• High-Speed Logic Probe (700986)
• Isolated Logic Probe (700987)
• 1 m Logic Probe (702911)
• 3 m Logic Probe (702912)
Types of Measurement Leads That Can Be Used
Use the following leads to connect to the point of measurement.
Connecting Leads That Can Be Used with Logic Probes 702911, 702912, and 700986
The following two types are available.
• Connecting lead (alligator clip, parts No. B9879PX)
This lead is primarily for connecting to contact circuits. The lead consists of 8 signal lines (red)
and 8 earth lines (black).
• Connecting lead (IC clip, parts No. B9879KX)
This lead is primarily for connecting to electronic circuits. The lead consists of 8 signal lines (red)
and 2 earth lines (black).
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IM DL850-03EN